1. Field of the Invention
One disclosed aspect of the embodiments relates a drawing apparatus configured to perform drawing on a substrate with a plurality of charged particle beams and a method of manufacturing an article using the drawing apparatus.
2. Description of the Related Art
A drawing apparatus configured to perform drawing on a substrate with a plurality of charged particle beams (an array of charged particle beams) has been discussed as a drawing apparatus used to manufacture a device such as a semiconductor integrated circuit (IC) (Japanese Patent Application Laid-Open No. 9-7538).
In such a drawing apparatus, when the number of charged particle beams is increased in order to increase a throughput, it is difficult to cope with aberration, a manufacturing error, or a change over time of an optical system configured to project a plurality of charged particle beams on a substrate. For this reason, a drawing apparatus that includes a deflector configured to deflect a charged particle beam for each of sub arrays constituting an array of charged particle beams has been discussed (Japanese Patent No. 3647128).
When a deflector configured to deflect a charged particle beam is provided for each sub array as discussed in Japanese Patent No. 3647128, sub arrays are arranged with space therebetween. In addition, not limited thereto, in an optical element (for example, a lens or a deflector) for a charged particle beam, spacers or joists are sometimes arranged at predetermined intervals in order to reduce bending of a thin plate such as an electrode included in the optical element. For this reason, in an array of charged particle beams, sub arrays are sometimes arranged with space therebetween.
When an array of charged particle beams is irradiated to a plurality of shot regions previously formed on a substrate, and drawing is performed on a plurality of shot regions while connecting drawing regions by sub arrays, a good throughput is obtained.
However, the following points need to be taken into consideration. In other words, the trajectory of a plurality of charged particle beams can be corrected in units of sub arrays by a deflector provided for each sub array. Further, correction in units of the sub arrays may be used to overlay a pattern to be drawn by a sub array on the position or the shape of a shot region previously formed on a substrate. For this reason, a method of performing drawing over two shot regions concurrently by a single sub array whose trajectory is adjusted based on the position or shape of one shot region is undesirable in terms of the overlay accuracy. In order to avoid this issue, it is desirable to cause a predetermined relation to be given among the size of a shot region formed on a substrate, the size of a sub array, and the size of space between sub arrays. For example, it is desirable to set the size of a sub array and the size of space to 1:1 and to set the size of a shot region to a natural-number multiple of a pitch between sub arrays. However, this setting limits the size of a chip since the size of a shot region is typically set to a natural-number multiple of the size of a chip to be manufactured.
Further, when charged particle beams at the outer edge of a sub array are not arrayed on a straight line (when an array is concave or convex), since a shot region is rectangular, it is difficult to cause the boundary of a drawing range by a sub array to match the boundary of a shot region. In this case, in order to prevent drawing from being performed over two shot regions concurrently by a single sub array, it is necessary to arrange shot regions at intervals of the width of the concavo-convex portion. In this case, the number of shot regions which can be arranged on a substrate decreases, and thus it is undesirable in terms of productivity.